1. Field of the Invention
The present invention relates to a retaining device for rolling-element, and more particularly to a retaining device for rolling-element which is applied to linear transmission unit.
2. Description of the Prior Arts
The linear transmission units of prior arts generally can be divided into two categories: First one is an independent individual retainer, and another one is a retainer made up of plural independent individuals. As shown in FIG. 4, wherein the slide block 11 is slidably mounted onto a rail, which is interiorly provided with a plurality of rolling-elements 20 and between every two neighboring rolling-elements 20 is provided with a single retainer 30 so as to prevent the rolling-elements 20 from striking with each other. It is time-consuming to assemble this linear transmission unit by alternatively inserting the rolling-element and single retainer in the slide block, furthermore, the retainers and the rolling-elements are coupled with each other closely, such will cause interference in the rolling of the rolling-element.
With reference to FIG. 5, which shows a retainer made up of plural independent individuals, wherein the retainer 31 is made up of plural independent spacers 311 linked together by a flexible chain 312, so as to confine the respective rolling-elements 20 in the intervals between paired neighboring spacers 311. The method of making this kind of retainer 31 is by putting the rolling-elements in a mould and made by plastic ejection molding, the material and the ejection molding machine should be high quality, thus the production cost is relatively increased. Furthermore, due to the special manufacturing method, the retainers and the rolling elements are coupled with each other closely, such will interfere in the rolling of the rolling-element.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages of the conventional retaining device for rolling-element.